History

The basic etiology of androgen insensitivity syndrome is a loss-of-function mutation in the AR gene.
[22, 23] Most cases of androgen insensitivity syndrome (AIS) are identified in the newborn period by the presence of inguinal masses, which later are identified as testes during surgery. Some patients are first seen in the teenage years for evaluation of primary amenorrhea. Many of these patients have a history of surgery for hernias and/or the presence of gonads in the inguinal canals, which were considered ovaries and returned to the abdomen. Adults with partial androgen insensitivity syndrome often have gynecomastia and impaired phallic growth in association with elevated circulating concentrations of testosterone, estradiol, and luteinizing hormone in puberty, while follicle-stimulating hormone levels are normal.
[24]

Patients with Kennedy disease have partial androgen resistance and are often underdiagnosed or misdiagnosed as having amyotrophic lateral sclerosis.
[13] They usually have gynecomastia and may develop tremor, muscle cramps, and sensory disturbances and slowly lose the ability to walk. Gynecomastia is postpubertal and men often do not have to shave daily.

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Physical

In newborns with complete androgen insensitivity syndrome (CAIS), the most frequent initial finding is unilateral or bilateral masses in the inguinal canals that are found to be testes during surgery. Associated hernias may or may not be present.
[25]

In adolescent patients, notable findings include inguinal masses. As with newborns, these masses may or may not be associated with hernias. In addition, adolescent patients have no pubic and axillary hair, with otherwise scanty body hair, and lack acne, although breasts are normal as a result of conversion of testosterone to estradiol. Women with complete androgen insensitivity syndrome often have reduced mean clitoral length compared with controls but are just as satisfied with sexual function as controls/healthy females.
[26, 27]

Newborns with partial androgen insensitivity syndrome (PAIS) can have a highly variable genital appearance. Adolescents may have pubic hair, although usually less than normal, and may have progressive clitoral enlargement and other signs of masculinization.

Postpubertal gynecomastia is present in most patients with Kennedy disease.

Robert P Hoffman, MD Professor and Program Director, Department of Pediatrics, Ohio State University College of Medicine; Pediatric Endocrinologist, Division of Pediatric, Endocrinology, Diabetes, and Metabolism, Nationwide Children's Hospital

Arlan L Rosenbloom, MD Adjunct Distinguished Service Professor Emeritus of Pediatrics, University of Florida College of Medicine; Fellow of the American Academy of Pediatrics; Fellow of the American College of Epidemiology